Vat-dyestuff of the dibenzanthrone series and process of making same



Patented May 17, 1932 UNITED STATES PATENT OFFICE LAND, ASSIGNORS 'ro SOCIETY on onEMIcAL r'n'iius'mit it? SWITZERLAND BAsnE, on iaAsisL,

VAT-DYESTUFF on THE DIIBENZANTI-IRONE starts AND eaoeiiss 0F ivtaiinve' No Drawing. Application filed September 12, September This invention relates to the manufacture of new vat dyestuffs by treating 132 :132 dibenzanthronyl with a nitrating agent and fusing the product thus obtained with a caustic alkali. The products of the manufacture are dyesti'lffs which dye blue grey. The dyeings on cotton may be distinguished by remarkable properties of fastness. The same products are obtained if previous to the melting operation, the nitrated Bz :Bz -dibenzanthronyl is reduced. By suit-able treatment, such as halogenation,-nitration, oxidation followed by alkylation, the new dyestuffs can be converted into further valuable products. All these new dyestuffs may be used as such or in the form of their leucoester salts.

Neither the position where the nitro-group enters the Bz :Bz -dibenzanthronyl molecule, nor the constitution of the vat-dyestuffs obtained therefrom is known.

The following examples illustrate the invention, the parts being by weight Example 1 45.8 parts of Bz :Bz -dibenzanthronyl of the formula .kept at the same temperature for 2 hours longer. While the mixed acids are being dropped into the liquid there occurs a change of colour from eosine red to brown red. The mass is poured on to ice and the precipitated brown yellow nitro-body, probably nitro- Bz Bzf-dibenzanthronyl is isolated by fil- 1929, Serial m. aeaese, and in switzeflaiia i 21, 1923'. I

tration in the usual manner It dissolvesin concentrated sulphuric acid to an eosine red solution. In distinction from the parent ma:-

terial which shows an intensely yellow-red fluorescence, the new body has only a feeble brownish fiuorescence in concentrated sulphuric acid. It is very sparingly soluble in boiling glacial acetic acid and in toluene. FY0511 hot nitrobenzene it can be recrystallZe Example 2 A mixture of 300 parts of caustic otash cooled and dissolved in water, the new dyestiifi' being separated fi-oiii the solution by means of aduri'ent of air;

The v new dyestufl' containing: a small mount of iiitrioge is a dark powder, sol bl in concentrated sinphurie acid to a (11111 blueviolet solution, from which when it is poured ihto'wat r, the dyestuff separates ii violetblue flocks. In boiling toluenethe dyestu dissolves sparingly to a solution which is pale blue and has a brown red fluorescence, hot nitrobenzene it dissolyes to a greenish: blue solution having a feeble brown fluor'escence and in boilinganiline it dissolves to a blue solution: Its vat is bright blue+violet having a blue grey bloom. Cotton dyed in "it is dyed very fast blue grey after efiposuie' to air and s'oapingf.

The new piqduct is distin uished fromtheness to keir-boilingof its dyeings, and an When essentially more valuable bluer shade of its dyeings.

Ewample a 5 parts of the vat dyestufl made'as described in Example 2 are suspended in 50 parts of nitrobenzene and into the mixture is dropped at the ordinary temperature in the course of hour and occasionally cooling a mix ture of 3.5 parts of nitric acid of 99-100 per cent. strength and parts of nitrobenzene. In ,the course of hourthe whole is heated to C. and kept for 6 hours at 50,55 C. Atthe .end of this period the liquid is mixed with a little water and .5

fluorescence and in aniline to a blue solution;

In its blue vat cotton is dyed, after exposure to air, blackish green shades, which by oxidation on the fibre, for example with Javells liquor, become deep black.

By halogenation the product of Example 2 is converted into a dyestufi which dies blue and by oxidation and alkylation into a dye stuff which dyes green.

What we claim is 1. As a step in the preparation of a new vat dyestuff, the treatment of the Bz :BzJ-dibenzanthronyl dissolved in sulphuric acid withan equivalent of nitric acid to produce a mono-nitrated B2 B zf-dibenzanthronyl.

2. As a step vin the preparation of a new vatdye'stufl', the heating of the mono-nitrated Bz :Bz -dibenzanthronyl with fused caustic alcoholic potash.

3. The preparation of a new vat dyestufl, consisting in' treating the B z Bz -dibenzanthronyl dissolved in sulphuric acid with an equivalent of nitric acid to produce a mononitrated Bz Bz dibenzanthronyl, and then treating the mono-nitrated Bz Bz -diben zanthronyl'with fused caustic alcoholic'potash.

' 4. The herein described new vat dyestufi' I obtainable according to claim 3, which forms a dark powder, containing a small amount of nitrogen, soluble in concentrated sulphuric acid to a dull blue-violet solution, from which when it is poured into water, the dyestufi? V separates in violet-blue flocks, sparingly soluble. in boiling toluene to a solution which is pale blue and has a brown red fluorescence,

V dissolving in hot nitrobenzene to a greenishblue solution having a feeble brown fluorescence and in boiling aniline to a bluesolution, giving a bright blue-violet vat with a blue-grey bloom, and dyeing cotton fast bluegrey tints which are very fast and strong.

In witness whereof we have hereunto signed our names this 3d day of September, 1929.

BERTRAM MAYER. HUGO SIEBENBU'RGER. KARL, KRAUER. 

